Symptoms
Consider the following scenario:
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              You enable user A and user B for Microsoft Lync Server 2010. 
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              User A is not a member of any Group Chat room in the environment. User B is added to a Group Chat room. 
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              You add a distribution list (DL) as a member to a Lync Server 2010, Group Chat room. You enable this chat room to send invitations to new members. 
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              You add both user A and user B to the DL. 
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              Both user A and user B sign in to Group Chat. 
In this scenario, user B receives the invitation but user A does not.
Cause
This issue occurs because of an automatic directory synchronization issue. The DL is not assigned a prinID. Therefore, the server does not detect the users in the DL and does not send the invitation.Note The term DL can refer to a distribution list, security group, organizational unit and so on.
Resolution
To resolve this issue, install the following cumulative update:
2670342 Description of the cumulative update for Lync Server 2010, Group Chat: February 2012
 
                         
				 
				